

function Back() {}

		

Back.easeIn = function ( p_t , p_b, p_c , p_d )
{
	return p_c * ( p_t /= p_d ) * p_t * ( 2.70158 * p_t - 1.70158 ) + p_b;
};


Back.easeOut = function (p_t, p_b, p_c, p_d)
{
	return p_c * ( ( p_t = p_t / p_d - 1) * p_t * ( 2.70158 * p_t + 1.70158) + 1 ) + p_b;
};

Back.easeInOut = function( p_t, p_b, p_c, p_d ) 
{
	if ( ( p_t /= p_d * 0.5 ) < 1 )
	{
		return p_c * 0.5 * ( p_t * p_t * ( ( 1.70158 * 1.525 + 1 ) * p_t - 1.70158 ) ) + p_b;
	}
	else
	{
		return p_c / 2 * ( ( ( p_t -= 2 ) * p_t * ( 1.70158 * 1.525 + 1 ) * p_t + 1.70158 ) + 2 ) + p_b;
	}
	
};